ECD SYSTEM(w/o Glow Plug Controller), Diagnostic DTC:P0112 and P0113

DTC Code DTC Name
P0112 Intake Air Temperature Circuit Low Input
P0113 Intake Air Temperature Circuit High Input

DESCRIPTION

A286043E01

The intake air temperature sensor is built into the Mass Air Flow (MAF) meter and senses the intake air temperature.

A thermistor built into the sensor changes its resistance value according to the intake air temperature.

The lower the intake air temperature, the greater the thermistor resistance value. The higher the intake air temperature, the lower the thermistor resistance value (See Fig. 1).

The intake air temperature sensor is powered by a 5 V supply from the THA terminal of the ECM, via resistor R. Resistor R and the intake air temperature sensor are connected in series. When the resistance value of the intake air temperature sensor changes in accordance with changes in the intake air temperature, the potential at terminal THA also changes. Based on this signal, the ECM increases the fuel injection volume to improve drivability with a cold engine.

Tip:

When the intake air temperature sensor output is outside the normal range, the ECM determines that there is a malfunction.

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0112

Intake Air Temperature Circuit Low Input

Intake air temperature sensor output is higher than 140°C (284°F).

(2 trip detection logic)

  • Short in intake air temperature sensor (built into mass air flow meter) circuit

  • Intake air temperature sensor (built into mass air flow meter)

  • ECM

Comes on

DTC stored

P0113

Intake Air Temperature Circuit High Input

Intake air temperature sensor output is less than -40°C (-40°F).

(2 trip detection logic)

  • Open in intake air temperature sensor (built into mass air flow meter) circuit

  • Intake air temperature sensor (built into mass air flow meter)

  • ECM

Comes on

DTC stored
Table 1. DTC Detection Drive Pattern

DTC No.

DTC Detection Drive Pattern

P0112

Ignition switch ON for approximately 15 seconds

P0113
Table 2. Related Data List

DTC No.

Data List

P0112

Intake Air

P0113
Tip:

  • If DTC P0112 or P0113 is stored, the following symptoms may appear:

    • Misfire

    • Combustion noise

    • Black smoke

    • White smoke

    • Lack of power

  • When DTC P0112 or P0113 is stored, check the intake air temperature by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / Intake Air.

Table 3. Reference

Temperature Displayed

Malfunction

-40°C (-40°F)

Open circuit

140°C (284°F)

Short circuit

WIRING DIAGRAM

A293327E01

CAUTION / NOTICE / HINT

Note:

When replacing the ECM, perform ECM Initialization and Registration.

Click hereClick here

Tip:

  • When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing a new ECM, perform all of the initialization and registration procedures for the "Learning Values Write" function by following the instructions shown on the GTS display.

  • Read freeze frame data using the GTS. Freeze frame data records the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, if the engine was warmed up or not, and other data from the time the malfunction occurred.

PROCEDURE

  1. READ VALUE USING GTS (INTAKE AIR)

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    4. Read the value.

      OK

      Same as actual intake air temperature.

      Result

      Result

      Proceed to

      -40°C (-40°F)

      A

      140°C (284°F)

      B

      Same as actual intake air temperature

      C
      Tip:

      • If there is an open circuit, the GTS indicates -40°C (-40°F).

      • If there is a short circuit, the GTS indicates 140°C (284°F).

    B

    READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)Click here

    C

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

    A

  2. READ VALUE USING GTS (CHECK FOR OPEN IN WIRE HARNESS)

    1. A199019C02

      *1

      Mass Air Flow Meter

      *2

      ECM

      *a

      Front view of wire harness connector

      (to Mass Air Flow Meter)

      Disconnect the mass air flow meter connector.

    2. Connect terminals B2-4 (THA) and B2-5 (E2) of the mass air flow meter connector on the wire harness side.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON and turn the GTS on.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    6. Read the value.

      Standard

      140°C (284°F).

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)Click here

    OK

  3. CONFIRM GOOD CONNECTION TO SENSOR. IF OK, REPLACE MASS AIR FLOW METER

    1. Replace the mass air flow meter.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

  4. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON and turn the GTS on.

    3. Clear the DTCs.

      Powertrain > Engine and ECT > Clear DTCs

    4. Turn the ignition switch off and wait for 30 seconds or more.

    5. Turn the ignition switch to ON and wait for 15 seconds or more.

    6. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes / Pending.

    7. Confirm that the pending DTC is not output again.

      Powertrain > Engine and ECT > Trouble Codes

    Result

    Proceed to

    NEXT
    NEXT

    END

  5. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

    1. Disconnect the mass air flow meter connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      B2-4 (THA) - A101-30 (THA)

      Always

      Below 1 Ω

      B2-5 (E2) - A101-31 (ETHA)

      Always

      Below 1 Ω

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  6. CONFIRM GOOD CONNECTION TO ECM. IF OK, REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  7. REPAIR OR REPLACE HARNESS OR CONNECTOR

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  8. READ VALUE USING GTS (CHECK FOR SHORT IN WIRE HARNESS)

    1. Disconnect the mass air flow meter connector.

    2. A200307C12

      *1

      Mass Air Flow Meter

      *2

      ECM

      Connect the GTS to the DLC3.

    3. Turn the ignition switch to ON and turn the GTS on.

    4. Reconnect the mass air flow meter connector.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / Intake Air.

      Powertrain > Engine and ECT > Data List

      Tester Display

      Intake Air

    6. Read the value.

      Standard

      -40°C (-40°F).

    Result

    Proceed to

    OK

    NG
    NG

    CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)Click here

    OK

  9. REPLACE MASS AIR FLOW METER

    1. Replace the mass air flow meter.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here

  10. CHECK HARNESS AND CONNECTOR (MASS AIR FLOW METER - ECM)

    1. Disconnect the mass air flow meter connector.

    2. Disconnect the ECM connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection

      Condition

      Specified Condition

      B2-4 (THA) or A101-30 (THA) - Body ground

      Always

      10 kΩ or higher

    Result

    Proceed to

    OK

    NG
    NG

    REPAIR OR REPLACE HARNESS OR CONNECTORClick here

    OK

  11. REPLACE ECM

    1. Replace the ECM.

      Click here

    Result

    Proceed to

    NEXT
    NEXT

    CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIREDClick here